Officials are probing how a 51-year-old highway bridge came to collapse in the Italian port city of Genoa yesterday, killing at least 26 people and injuring 16 others as it sent dozens of vehicles tumbling into a heap of concrete and twisted steel.

How California's sea otters came back from the brink of extinction

They were once believed to have been hunted into extinction, but by some miracle, California sea otters are still here.

The charismatic creatures were targeted in the 1800s and early 1900s, shot and speared for their beautiful furs which were made into stylish coats.

They were thought to have gone extinct until 1938 when, by surprise, a group of about 50 were found to have survived on a deserted bay in Big Sur on California’s coast.

Sea Otters were shot and speared for their furs. ()

Their numbers are growing slowly with the most recent count coming in at around 3,272.

However wildlife photographer and self-appointed sea otter advocate Kim Steinhardt told 9NEWS “that’s not many”, and tourists are having a big impact on the numbers as they get into the water to get a closer look.

"If they don't get any closer they're not really going to threaten those otters or disturb them,” Mr Steinhardt said.

“What we don’t want to see them do is turn and go at the otters and freak the otters out.”